There seems to be a lot of topic modelling going on at the moment. Any why not? Projects like Mining the Dispatch are demonstrating the possibilities. Tools like Mallet are making it easy. And generous DHers like Ted Underwood and Scott Weingart are doing a great job explaining what it is and how it works.
I’ve talked briefly about using topic modelling to explore digitised newspapers, something that the Mapping Texts project has also been investigating. But I’ve also been following with interest Chad Black’s use of algorithmic techniques, including topic modelling, to look for local variations amidst the legal system of the early modern Spanish empire.
As part of the Invisible Australians project, Kate and I are exploring the bureaucracy of the White Australia Policy. In particular, we’re interested in the interaction between policy and practice, between the highly-centralised bureaucracy and the activities of individual port officials. Like Chad, we’re interested in mapping local variations — to try and understand the bureaucracy from the point of view of an individual forced to live within its restrictions.
I recently gave a presentation about the project at Digital Humanities Australasia (post coming soon!), and in preparation I decided to try a few topic modelling experiments. They were very simple, but I was impressed by the possibilities for exploring archival systems.
The problem I started with was this. The workings of the White Australia Policy are well documented by records held by the National Archives of Australia. Some series within the archives are specifically related to the operations of the policy — such as those containing many thousands of CEDTs. But there are also general correspondence series created by the customs offices in each state, as well as the Commonwealth Department of External Affairs which administered the Immigration Restriction Act (responsibility was later taken by the Department of Home and Territories and it’s successors). These general correspondence series are important, because they often include details of difficult or controversial cases — those that required a policy judgment, or prompted a change in existing practices. But how do you find relevant files within series that can contain large numbers of items?
Series A1, for example, is a correspondence series created by the Department of External Affairs. It contains more than 60,000 items. Past research tells us that amongst these 60,000 files are records of important policy discussions relating to White Australia. But these files tend to be labelled with the names of the people involved, so unless you know the names in advance they can be difficult to find.
Mitchell Whitelaw’s A1 Explorer, part of the Visible Archive project, lets you to explore the contents of Series A1 in a easy and engaging way. But while the A1 Explorer provides new opportunities for discovery, it doesn’t offer the fine-grained analysis we need to sift out the files we’re after. And so… topic modelling.